HVAC System

CIRCUIT DESCRIPTION
The calibrations for the heater and A/C control are stored in EEPROM. When the ignition is first turned On, the controller performs internal tests on the EEPROM to determine if the EEPROM is programmed.

CONDITIONS FOR SETTING THE DTC
^ The test byte in EEPROM has an incorrect value (EEPROM not programmed).
^ This fault is immediately recognized when the ignition is first turned On.

ACTION TAKEN WHEN THE DTC SETS
^ Stores a DTC 52 in the controllers memory.
^ The heater and A/C control uses default values.

CONDITIONS FOR CLEARING THE DTC
^ Programming the heater and A/C control.
^ The use of a scan tool.
^ A history DTC will clear after 20 consecutive ignition cycles if the condition for the fault is no longer present.

TEST DESCRIPTION

Steps 1-5:

The number(s) below refer to the step number(s) on the diagnostic table.
2. Calibrations for the heater and A/C control module are stored in EEPROM. Because this DTC sets when a test byte is incorrect in EEPROM, this step reprograms the module.